[Feature Request] or [Bug]? Playables Animation - Linear Extrapolation - Lerp beyond [0,1]

This may be a fairly fringe feature request. That said: I'm currently looking at doing some procedural animation within Unity's Playable system. I've started by blending several animations (really just key-frames) together. Seems to work well. Trouble is, when I try to blend outside the normalized range I get some unexpected behaviors.

I'm aware the documentation for SetInputWeight says "Should be between 0 and 1" however I don't know of any mathematical limitation for this. If correct weights are set outside the bounds of 0 and 1 the animation should still look good.

I.E.
//alpha = -0.5f
//1.0f - alpha = 1.5;
posNew = pos1 * (1.0f - alpha) + pos2 * alpha;
posNew = pos1 * 1.5f + pos2 * -0.5f;

Should end up with a point that's along the line but outside of the line-segment between pos1 and pos2. In this case it would be away from pos1 in the direction defined by the vector (pos1 - pos2).normalized.

It's also possible Unity already does this and I'm making an error in my code.

Please let me know. Thanks!

Edit: Made changes to correct math

 

Bump

 

Alright, I've talked to someone in the know at Unity about this. Turns out because Playables are generic this can't really be done. For example: what does it mean to extrapolate an audio clip? Might be more hope for a solution in the future.

Hope this helps someone looking for the answer to this odd question.